power: supply: Add Lenovo Yoga C630 EC driver

The Qualcomm Snapdragon-based Lenovo Yoga C630 has some sort of EC
providing AC-adapter and battery status, as well as USB Type-C altmode
notifications for Displayport operation.

The Yoga C630 ships with Windows, where these operations primarily are
implemented in ACPI, but due to various issues with the hardware
representation therein it's not possible to run Linux on this
information. As such this is a best-effort re-implementation of these
operations, based on the register map expressed in ACPI and a fair
amount of trial and error.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/power/supply/Kconfig

@@ -905,4 +905,15 @@ config BATTERY_UG3105
 	  device is off or suspended, the functionality of this driver is
 	  limited to reporting capacity only.
 
+config LENOVO_YOGA_C630_EC
+	tristate "Lenovo Yoga C630 EC battery driver"
+	depends on DRM
+	depends on I2C
+	help
+	  Driver for the Embedded Controller in the Qualcomm Snapdragon-based
+	  Lenovo Yoga C630, which provides battery information and USB Type-C
+	  altmode notifications.
+
+	  Say M or Y here to include this support.
+
 endif # POWER_SUPPLY

drivers/power/supply/Makefile

@@ -109,3 +109,4 @@ obj-$(CONFIG_BATTERY_ACER_A500)	+= acer_a500_battery.o
 obj-$(CONFIG_BATTERY_SURFACE)	+= surface_battery.o
 obj-$(CONFIG_CHARGER_SURFACE)	+= surface_charger.o
 obj-$(CONFIG_BATTERY_UG3105)	+= ug3105_battery.o
+obj-$(CONFIG_LENOVO_YOGA_C630_EC)	+= yoga-c630-ec.o